Early treatment response as a predictor of ongoing weight loss in obesity treatment.

OBJECTIVES: This study examined early treatment response in obesity treatment, defined as early change in body mass index (BMI) and early change in eating behaviour, as a predictor of ongoing weight loss in obese patients.
METHODS: We conducted a repeated measures analysis of eating behaviour, emotional factors (depression, stress, perfectionism) and BMI, over a 9 month period. Subjects were 344 females, aged 18-65 (mean = 41.8), with a BMI of at least 25 (mean BMI = 33.7), engaged in very-low calorie (VLCD) or low-calorie (LCD) diets.
RESULTS: Multi-level modelling identified four significant predictors of ongoing weight loss (weight loss occurring between 5 weeks and 9 months after the start of treatment). These included: type of diet, early BMI change (start to 5 weeks), number of weigh-ins and the early change in uncontrolled eating (start to 5 weeks). Estimates based on multi-level modelling indicate that patients with strong versus weak early treatment responses would be expected to show large differences in ongoing weight loss.
CONCLUSIONS: Early improvements in eating behaviour and weight appear to have additive effects in the prediction of ongoing weight change. Future research is required to identify the optimal rate of weight loss, whether there are critical periods for behaviour change, and factors which influence the likelihood of early behaviour change.